Dr Reynolds, 50, had been tipped for the top job at Telecom since March and is due to take up his new role in late September.

He is currently CEO of BT Wholesale, the wholesale business of British-based telecommunications and IT company BT Group.

He joined BT in 1983 after completing a doctorate in geology at the University of London. His career has included senior leadership roles in sales and marketing, strategy, information systems, broadband, and guiding BT's wholesale business through the complex process of operational separation.